A UV nanoimprint method is one method of producing a resist film having a predetermined pattern shape on a substrate such as a substrate to be processed and has, for example, the following manufacturing process including steps (a) to (d):    (a) placing a resist (photocurable composition);    (b) bringing the photocurable composition and a mold having a fine irregular pattern formed on its surface into contact with each other;    (c) irradiating the photocurable composition with light; and    (d) releasing the photocurable composition and the mold from each other after the irradiating.
It should be noted that the pattern shape of the resist film produced through the manufacturing process including the steps (a) to (d) is formed by transferring the concavo-convex of the mold onto the resist film placed on the substrate.
By the way, upon utilization of the UV nanoimprint method, to reduce a force needed for releasing the mold from the resist cured product in the mold release step (step (d)), i.e., a mold release force has been an important issue. This is because of the following reason. When the mold release force is large, problems such as the occurrence of a defect in the pattern and a reduction in positioning accuracy due to the floating of the substrate from a stage arise.
Available as a method of solving the problems is a method proposed in PTL 1. Specifically, the following method has been proposed. A photocurable composition to which a photosensitive gas generating agent that generates a gas such as nitrogen or carbon dioxide through a photoreaction has been added is used. When the method is employed, an interfacial bond between the mold and the photocurable composition is cleaved by the pressure of a gas generated in the light irradiation step, whereby the mold release force is reduced.
However, the method proposed in PTL 1 has involved the following problem. The light irradiation to be performed for generating the gas requires a long time period and hence productivity is low.